Musical instrument



March 11, 1930. v. s. TRUETT ET AL MUSICAL INSTRUMENT Filed March '7, 1927 2K mwfiw m 76 0 m2 v WA M E 45 a v W Patented Mar. 11, 1930 UNITED STATES PATENT. OFFICE VELMA S. TRUETT AND HARRY H. GEGR-GE, OF SAN FRANCISCO, CALIFORNIA MUSICAL INSTRUMENT Application filed March 7, 1927.

The invention relates to musical instruments and particularly to stringed instruments.

An object of the invention is to provide means for improving the quality of the tones of certain stringed instruments.

Another object of the invention is the pro vision of resonator means within the body of an instrument, such as a banjo, for the purpose of increasing the depth and volume of the tones produced by it.

The invention possesses other objects and valuable features, some of which will be set forth in the following description of the in vention which is illustrated in the drawings forming part of the specification. It is to be understood that we do not limit ourselves to the showing made by the said description and drawings, as we may adopt varying forms of the invention within the scope of the claims.

Referring to the drawings:

The figure is a vertical sectional view taken on the longitudinal median plane of the body of a banjo equipped with the resonator flange and sound ring.

Broadly, the invention comprises the inclusion within the body of a stringed instrument of an auxiliary sound boX or chamber which will give depth and color to the tones produced by the instrument, and greatly in crease their volume. Our invention preterably takes the form of a resonator flange, having one end mounted on the inside of the rim and the other end left free to vibrate.

Banjos as heretofore made produced a staccato tone with little or no resonance, and one which has a small carrying power. These tones are frequently termed tin-panny and 40. are chiefly desired to accentuate the rhythm of the music. For this reason the range of usefulness of the banjo has been somewhat restricted. By the inclusion of our invention, the tones of a banjo become resonant, have a singing quality and their carrying power is surprisingly increased. A banjo so equipped becomes more desirable as an orchestral instrument because of its increased volume which is acquired without impairing the qualities which peculiarly adapt it to that Serial No. 173,273.

use. On the other hand, due to the improved tonal qualities the banjo can be used as a concert or parlor instrument.

Our invention is designed to be used in a banjo or similar instrument comprising a rim 2, provided with the usual lugs 3 in which are secured one end of the tensioning bolts l which are Pl'OVlQGCl to hold the head 6 in position. The head is stretched across the upper periphery of a band 7 which is mounted in the rabbet 8 of the rim. Mounted on the head in the usual manner is a bridge 9 across which the strings 11 extend to the tail piece 12 which is suitably anchored on the side of the instrument.

In detail our invention comprises a resonator flange 16, preferably formed of metal, and having a reentrant angle of about 110 adjacent its center. The width of this flange is preferably approximately the same Width as the rim. An anchoring flange 17 is provided on one of the peripheries of the resonator flange to enable it to be secured to the top of the rim 2 within which it is arranged. When the resonator flange is so arranged within the rim, the other periphery 18 does not contact with the instrument and is therefore free to vibrate. A sound box or chamber is thus formed having a restricted area adjacent its center. The outward flare of the lower periphery of the resonator flange forms what may be termed a bell-mouth which opens toward the lower side of the instrument. When the instrument is played this bell mouth portion of the flange is set into vibration, amplifying the sound and directing it toward the reflector or resonator plate 21, arranged adjacent the lower periphery of the run. The greater part of the sound waves are then reflected by the plate thru the apertures 22 around the side thereof and some of the sound waves are undoubtedly thrown back thru the head of the instrument. The effect produced by the structure shown is to impart a sweet singing tone to the music and to very materially increase its resonance and tone volume.

The resonator plate 21 of our invention is preferably formed entirely of metal and comprises a plate having a greater diameter the diameter of the rim and provided with an annular reentrant flange 23 which is so shaped that it fits snugly around the lower periphery of the rim to hold the resonator plate in position. The plurality of the apertures 22 arranged around the flange 23 offer a substantially unrestricted passage for the sound waves.

While the portion of our structure just described is alone suflicient to give a very much superior tone than has heretofore been produced, we have found that even better results can be obtained by the provision of a special sound ring 26 which is preferably formed integral with the band 7 of the exterior of the instrument. Particular attention has been given to the shape of the sound ring in order to secure the desired depth of tone. The exterior of the sound rin comprises a cylindrical side 7 corresponding to the band in the ordinary banjo. The lower end of the cylindrical side seats in the rabbet 8 of the rim 2 in the usual manner. The inner side of the sound ring is preferably axial- 1 curved, the portion of the curve adjacent t e head 6 being flatter than the portion adjacent the resonator flange 16. Disposed around the sound ring are a plurality of apertures 27 thru which the sound waves created within the sound ring may pass into the inner resonator chamber.

In order to sufliciently strengthen the sound ring sothat the pressure of the head being stretched thereacross will not cause it to collapse, we have provided a channel or bead 28 inwhich a metallic reinforcing ring is secured. It will be apparent that by the use of this structure that the tone formed within the sound ring and discharged thru the apertures 27 is amplified by the resonator chamber or bell mouth and reflectedby the resonator plate 21. The yibrationsstruck up by the head in the metallic sound ring and directl transmitted into the metallic resonator nge 16 so that by both these methods the tones of the instrument are greatly improved.

We' claim:

1. In a stringed musical instrument a rim, ahead arranged on one side of the rim, a reflector plate closing the opposite side of the ring-and a bell-mouth resonator flange mounted-on the inside of the rim and opening toward the reflector plate.

2. In a stringed musical instrument, a rim, 8. head arranged on said rim, an apertured sound ring within the rim beneath the head and a resonator flange forming a sound chamher having a restricted area adjacent its center within the rim and beneath the sound ring.

3. Ina stringed musical instrument, a rim, a head arranged on the rim, and a sound ring beneath the head, said sound ring comprising a cylindrical outer wall and an axially curved inner wall.

4. In a stringed musical instrument, a rim, :1 head arran ed on the rim, and a sound ring beneath the ead, said sound ring comprising a cylindrical outer wall and an axially curved inner wall, the curvature of said inner wall being non-uniform and flatter adjacent the head.

5. In a stringed musical instrument, a rim, a head arranged on the rim, a sound ring heneath the head, said sound ring comprisin a cylindrical outer wall and an axially curve inner wall, and a resonator flange within the rim and beneath the sound ring.

6. In a stringed musical instrument, a rim, a head arranged on the rim, a sound ring heneath the head, said sound ring comprising a cylindrical outer wall and an axially curved inner wall and a resonator flange within the rim and beneath the sound ring, said flange having a free vibratile edge.

7. In a stringed musical instrument, a rim, a head arranged on the rim, and a resonator flange within the rim, said resonator flange having a constricted portion adiacent its center and a free vibratile bell mouth substantially equal to the rim in diameter.

8. In a stringed musical instrument, a rim, a head arranged on the rim, an apertured sound ring arranged on the rim beneath the head, and a resonator flange secured inmo' diately beneath the sound ring and forming a resonance chamber having a restricted 81m adjacent its center within the rim.

9. In a stringed musical instrument, a rim,

a head arranged on the rim, an apertured sound ring arranged on the rim beneath the head, and a resonator flange beneath the ward ring and secured thereby.

10. In a stringed muslcal instrument, a rim, a head arranged on one side of the rim, a reflector plate closing the opposite side of the rim, a sound ring beneath the head having an axially curved inner wall,- and a belt mouth resonator flange mounted inside ot' the rim and opening toward the reflector plate.

11. In a strin ed musical instrument, a rim, a head arrange on one side of the rim, a reflector plate closing the opposite side of the rim, a sound ring beneath the head, and a belt mouth resonator flange mounted inside elf the rim and opening toward the reflector plate.

In testimony whereof, we have hereunto set our hands.

VELMA S: TRUETT. HARRY H. GEORGE. 

